The present invention relates to a television special effects system, and more particularly, to one that provides variable speed for a video tape recorder (VTR) during the playback mode.
Up until now, it has been conventional to achieve variable playback speeds of a record segment using a variable DC voltage in an open loop system; however this is not an accurate way of achieving variable playback speeds. U.S. patent application Ser. No. 94,690, filed Nov. 15, 1979, shows a motor speed control circuit that is capable of highly accurate and reproducable motor speeds in response to a speed command signal. However, it does not show in detail a means for obtaining the motor speed control signal.
It is therefore desirable to have a motor speed control signal for controlling a motor speed control circuit. It is also desirable to control the rate of change of a speed-change special effect from an initial speed to a final speed.